The project is directed at studying humoral factors which alter phagocytic cell function and become apparent during various disease states. Studies involve: 1) the role and mechanism by which polymeric myeloma IgA is able to suppress neutrophil chemotaxis and phagocytosis and 2) the nature and function of a 4S factor directed chemotactic inhibitor which appears as a result of hemodialysis. In vitro and in vivo studies in mice are being conducted to determine the role of these factors in delayed and acute inflammatory responses. Additional work is being performed to determine the effect of chemotaxis on human neutrophils surface receptors and metabolism. Finally, studies dealing with the effect of various plant lectins on neutrophil function and membrane receptors are in progress. In summary, this project is directed at the study of neutrophil dysfunction, its potential regulation by humoral factors, variations in function with disease, and analysis of various PMN membrane receptors and their function.